New Adhesive Design and Evaluation for Bumpless Interconnects and Wafer-On-Wafer (WOW) Integration

Abstract

The material viscosities of permanent and temporary adhesives were examined using the rigid body pendulum method to reveal a suitable for the wafer bonding process at 100 °C. Properties suited for the debonding process The adhesive is applied to wafer-on-wafer (WOW) stacking with bumpless dual-damascene interconnect (via-last after bonding) technology, which enables multilevel stacking using ultra-thin wafers of several micrometers or less at low cost.